Sebastian Risi

Prof. Dr. Sebastian Risi


Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 March 2020 in IEEE Transactions on Games
Verified
Journal Article
Closed access
NJNiels Justesen
Niels Justesen
PBPhilip Bontrager
Philip Bontrager
JTJulian Togelius
Julian Togelius
SRSebastian Risi
Sebastian Risi
In this article, we review recent Deep Learning advances in the context of how they have been applied to play different types of video games such as first-person shooters, arcade games, and real-time strategy games. We analyze the unique requirements that different game genres pose to a deep learning system and highlight important open challenges in the context of applying these machine learning methods to video games, such as general game playing, dealing with extremely large decision spaces and sparse rewards.

8 October 2020 in Neural Computing and Applications
Verified
Journal Article
Closed access
PDF file
JLJialin Liu
Jialin Liu
SSSam Snodgrass
Sam Snodgrass
AKAhmed Khalifa
Ahmed Khalifa
SRSebastian Risi
Sebastian Risi
GYGeorgios N. Yannakakis
Georgios N. Yannakakis
JTJulian Togelius
Julian Togelius

1 December 2018 in Neural Networks
Verified
Journal Article
Open access
ASAndrea Soltoggio
Andrea Soltoggio
KSKenneth O. Stanley
Kenneth O. Stanley
SRSebastian Risi
Sebastian Risi
Biological neural networks are systems of extraordinary computational capabilities shaped by evolution, development, and lifelong learning. The interplay of these elements leads to the emergence of biological intelligence. Inspired by such intricate natural phenomena, Evolved Plastic Artificial Neural Networks (EPANNs) employ simulated evolution in-silico to breed plastic neural networks with the aim to autonomously design and create learning systems. EPANN experiments evolve networks that include both innate properties and the ability to change and learn in response to experiences in different environments and problem domains. EPANNs' aims include autonomously creating learning systems, bootstrapping learning from scratch, recovering performance in unseen conditions, testing the computational advantages of particular neural components, and deriving hypotheses on the emergence of biological learning. Thus, EPANNs may include a large variety of different neuron types and dynamics, network architectures, plasticity rules, and other factors. While EPANNs have seen considerable progress over the last two decades, current scientific and technological advances in artificial neural networks are setting the conditions for radically new approaches and results. Exploiting the increased availability of computational resources and of simulation environments, the often challenging task of hand-designing learning neural networks could be replaced by more autonomous and creative processes. This paper brings together a variety of inspiring ideas that define the field of EPANNs. The main methods and results are reviewed. Finally, new opportunities and possible developments are presented.

3 August 2020 in Nature Machine Intelligence
Verified
Journal Article
Closed access
PDF file
SRSebastian Risi
Sebastian Risi
JTJulian Togelius
Julian Togelius

26 October 2015 in IEEE Transactions on Computational Intelligence and AI in Games
Verified
Journal Article
Closed access
SRSebastian Risi
Sebastian Risi
JTJulian Togelius
Julian Togelius
This paper surveys research on applying neuroevolution (NE) to games. In neuroevolution, artificial neural networks are trained through evolutionary algorithms, taking inspiration from the way biological brains evolved. We analyze the application of NE in games along five different axes, which are the role NE is chosen to play in a game, the different types of neural networks used, the way these networks are evolved, how the fitness is determined and what type of input the network receives. The paper also highlights important open research challenges in the field.

1 October 2012 in Artificial Life
Verified
Journal Article
Closed access
SRSebastian Risi
Sebastian Risi
KSKenneth O. Stanley
Kenneth O. Stanley
Intelligence in nature is the product of living brains, which are themselves the product of natural evolution. Although researchers in the field of neuroevolution (NE) attempt to recapitulate this process, artificial neural networks (ANNs) so far evolved through NE algorithms do not match the distinctive capabilities of biological brains. The recently introduced hypercube-based neuroevolution of augmenting topologies (HyperNEAT) approach narrowed this gap by demonstrating that the pattern of weights across the connectivity of an ANN can be generated as a function of its geometry, thereby allowing large ANNs to be evolved for high-dimensional problems. Yet the positions and number of the neurons connected through this approach must be decided a priori by the user and, unlike in living brains, cannot change during evolution. Evolvable-substrate HyperNEAT (ES-HyperNEAT), introduced in this article, addresses this limitation by automatically deducing the node geometry from implicit information in the pattern of weights encoded by HyperNEAT, thereby avoiding the need to evolve explicit placement. This approach not only can evolve the location of every neuron in the network, but also can represent regions of varying density, which means resolution can increase holistically over evolution. ES-HyperNEAT is demonstrated through multi-task, maze navigation, and modular retina domains, revealing that the ANNs generated by this new approach assume natural properties such as neural topography and geometric regularity. Also importantly, ES-HyperNEAT's compact indirect encoding can be seeded to begin with a bias toward a desired class of ANN topographies, which facilitates the evolutionary search. The main conclusion is that ES-HyperNEAT significantly expands the scope of neural structures that evolution can discover.